fix parsing of storage constraints

Parses the storage constraints when deploying applications. Before this
change the storage constraints where not parsing, resulting in an error
when deploying bundles that contained applications with storage
definitions.

Author: Luís Simas

juju/model.py

@@ -29,6 +29,7 @@
 from .client import client, connector
 from .client.overrides import Caveat, Macaroon
 from .constraints import parse as parse_constraints
+from .constraints import parse_storage_constraint
 from .controller import Controller, ConnectedController
 from .delta import get_entity_class, get_entity_delta
 from .errors import JujuAPIError, JujuError, JujuModelConfigError, JujuBackupError
@@ -2115,7 +2116,7 @@ async def _deploy(self, charm_url, application, series, config,
                 devices=devices,
                 dryrun=False,
                 placement=placement,
-                storage=storage,
+                storage={k: parse_storage_constraint(v) for k, v in (storage or dict()).items()},
                 trust=trust,
                 base=charm_origin.base,
                 channel=channel,
@@ -2150,7 +2151,7 @@ async def _deploy(self, charm_url, application, series, config,
                 endpoint_bindings=endpoint_bindings,
                 num_units=num_units,
                 resources=resources,
-                storage=storage,
+                storage={k: parse_storage_constraint(v) for k, v in (storage or dict()).items()},
                 placement=placement,
                 devices=devices,
                 attach_storage=attach_storage,